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ultralytics.utils.tal.TaskAlignedAssigner

قواعد: Module

تعيين محاذاة للمهام لاكتشاف الكائن.

تقوم هذه الفئة بتعيين كائنات الحقيقة الأساسية (gt) إلى نقاط الارتساء استنادا إلى المقياس المحاذي للمهمة ، والذي يجمع بين كليهما معلومات التصنيف والتوطين.

سمات:

اسم نوع وصف
topk int

عدد أفضل المرشحين للنظر فيها.

num_classes int

عدد فئات الكائنات.

alpha float

معلمة ألفا لمكون التصنيف لمقياس محاذاة المهام.

beta float

المعلمة التجريبية لمكون الترجمة لمقياس محاذاة المهام.

eps float

قيمة صغيرة لمنع القسمة على الصفر.

شفرة المصدر في ultralytics/utils/tal.py
class TaskAlignedAssigner(nn.Module):
    """
    A task-aligned assigner for object detection.

    This class assigns ground-truth (gt) objects to anchors based on the task-aligned metric, which combines both
    classification and localization information.

    Attributes:
        topk (int): The number of top candidates to consider.
        num_classes (int): The number of object classes.
        alpha (float): The alpha parameter for the classification component of the task-aligned metric.
        beta (float): The beta parameter for the localization component of the task-aligned metric.
        eps (float): A small value to prevent division by zero.
    """

    def __init__(self, topk=13, num_classes=80, alpha=1.0, beta=6.0, eps=1e-9):
        """Initialize a TaskAlignedAssigner object with customizable hyperparameters."""
        super().__init__()
        self.topk = topk
        self.num_classes = num_classes
        self.bg_idx = num_classes
        self.alpha = alpha
        self.beta = beta
        self.eps = eps

    @torch.no_grad()
    def forward(self, pd_scores, pd_bboxes, anc_points, gt_labels, gt_bboxes, mask_gt):
        """
        Compute the task-aligned assignment. Reference code is available at
        https://github.com/Nioolek/PPYOLOE_pytorch/blob/master/ppyoloe/assigner/tal_assigner.py.

        Args:
            pd_scores (Tensor): shape(bs, num_total_anchors, num_classes)
            pd_bboxes (Tensor): shape(bs, num_total_anchors, 4)
            anc_points (Tensor): shape(num_total_anchors, 2)
            gt_labels (Tensor): shape(bs, n_max_boxes, 1)
            gt_bboxes (Tensor): shape(bs, n_max_boxes, 4)
            mask_gt (Tensor): shape(bs, n_max_boxes, 1)

        Returns:
            target_labels (Tensor): shape(bs, num_total_anchors)
            target_bboxes (Tensor): shape(bs, num_total_anchors, 4)
            target_scores (Tensor): shape(bs, num_total_anchors, num_classes)
            fg_mask (Tensor): shape(bs, num_total_anchors)
            target_gt_idx (Tensor): shape(bs, num_total_anchors)
        """
        self.bs = pd_scores.shape[0]
        self.n_max_boxes = gt_bboxes.shape[1]

        if self.n_max_boxes == 0:
            device = gt_bboxes.device
            return (
                torch.full_like(pd_scores[..., 0], self.bg_idx).to(device),
                torch.zeros_like(pd_bboxes).to(device),
                torch.zeros_like(pd_scores).to(device),
                torch.zeros_like(pd_scores[..., 0]).to(device),
                torch.zeros_like(pd_scores[..., 0]).to(device),
            )

        mask_pos, align_metric, overlaps = self.get_pos_mask(
            pd_scores, pd_bboxes, gt_labels, gt_bboxes, anc_points, mask_gt
        )

        target_gt_idx, fg_mask, mask_pos = self.select_highest_overlaps(mask_pos, overlaps, self.n_max_boxes)

        # Assigned target
        target_labels, target_bboxes, target_scores = self.get_targets(gt_labels, gt_bboxes, target_gt_idx, fg_mask)

        # Normalize
        align_metric *= mask_pos
        pos_align_metrics = align_metric.amax(dim=-1, keepdim=True)  # b, max_num_obj
        pos_overlaps = (overlaps * mask_pos).amax(dim=-1, keepdim=True)  # b, max_num_obj
        norm_align_metric = (align_metric * pos_overlaps / (pos_align_metrics + self.eps)).amax(-2).unsqueeze(-1)
        target_scores = target_scores * norm_align_metric

        return target_labels, target_bboxes, target_scores, fg_mask.bool(), target_gt_idx

    def get_pos_mask(self, pd_scores, pd_bboxes, gt_labels, gt_bboxes, anc_points, mask_gt):
        """Get in_gts mask, (b, max_num_obj, h*w)."""
        mask_in_gts = self.select_candidates_in_gts(anc_points, gt_bboxes)
        # Get anchor_align metric, (b, max_num_obj, h*w)
        align_metric, overlaps = self.get_box_metrics(pd_scores, pd_bboxes, gt_labels, gt_bboxes, mask_in_gts * mask_gt)
        # Get topk_metric mask, (b, max_num_obj, h*w)
        mask_topk = self.select_topk_candidates(align_metric, topk_mask=mask_gt.expand(-1, -1, self.topk).bool())
        # Merge all mask to a final mask, (b, max_num_obj, h*w)
        mask_pos = mask_topk * mask_in_gts * mask_gt

        return mask_pos, align_metric, overlaps

    def get_box_metrics(self, pd_scores, pd_bboxes, gt_labels, gt_bboxes, mask_gt):
        """Compute alignment metric given predicted and ground truth bounding boxes."""
        na = pd_bboxes.shape[-2]
        mask_gt = mask_gt.bool()  # b, max_num_obj, h*w
        overlaps = torch.zeros([self.bs, self.n_max_boxes, na], dtype=pd_bboxes.dtype, device=pd_bboxes.device)
        bbox_scores = torch.zeros([self.bs, self.n_max_boxes, na], dtype=pd_scores.dtype, device=pd_scores.device)

        ind = torch.zeros([2, self.bs, self.n_max_boxes], dtype=torch.long)  # 2, b, max_num_obj
        ind[0] = torch.arange(end=self.bs).view(-1, 1).expand(-1, self.n_max_boxes)  # b, max_num_obj
        ind[1] = gt_labels.squeeze(-1)  # b, max_num_obj
        # Get the scores of each grid for each gt cls
        bbox_scores[mask_gt] = pd_scores[ind[0], :, ind[1]][mask_gt]  # b, max_num_obj, h*w

        # (b, max_num_obj, 1, 4), (b, 1, h*w, 4)
        pd_boxes = pd_bboxes.unsqueeze(1).expand(-1, self.n_max_boxes, -1, -1)[mask_gt]
        gt_boxes = gt_bboxes.unsqueeze(2).expand(-1, -1, na, -1)[mask_gt]
        overlaps[mask_gt] = self.iou_calculation(gt_boxes, pd_boxes)

        align_metric = bbox_scores.pow(self.alpha) * overlaps.pow(self.beta)
        return align_metric, overlaps

    def iou_calculation(self, gt_bboxes, pd_bboxes):
        """IoU calculation for horizontal bounding boxes."""
        return bbox_iou(gt_bboxes, pd_bboxes, xywh=False, CIoU=True).squeeze(-1).clamp_(0)

    def select_topk_candidates(self, metrics, largest=True, topk_mask=None):
        """
        Select the top-k candidates based on the given metrics.

        Args:
            metrics (Tensor): A tensor of shape (b, max_num_obj, h*w), where b is the batch size,
                              max_num_obj is the maximum number of objects, and h*w represents the
                              total number of anchor points.
            largest (bool): If True, select the largest values; otherwise, select the smallest values.
            topk_mask (Tensor): An optional boolean tensor of shape (b, max_num_obj, topk), where
                                topk is the number of top candidates to consider. If not provided,
                                the top-k values are automatically computed based on the given metrics.

        Returns:
            (Tensor): A tensor of shape (b, max_num_obj, h*w) containing the selected top-k candidates.
        """

        # (b, max_num_obj, topk)
        topk_metrics, topk_idxs = torch.topk(metrics, self.topk, dim=-1, largest=largest)
        if topk_mask is None:
            topk_mask = (topk_metrics.max(-1, keepdim=True)[0] > self.eps).expand_as(topk_idxs)
        # (b, max_num_obj, topk)
        topk_idxs.masked_fill_(~topk_mask, 0)

        # (b, max_num_obj, topk, h*w) -> (b, max_num_obj, h*w)
        count_tensor = torch.zeros(metrics.shape, dtype=torch.int8, device=topk_idxs.device)
        ones = torch.ones_like(topk_idxs[:, :, :1], dtype=torch.int8, device=topk_idxs.device)
        for k in range(self.topk):
            # Expand topk_idxs for each value of k and add 1 at the specified positions
            count_tensor.scatter_add_(-1, topk_idxs[:, :, k : k + 1], ones)
        # count_tensor.scatter_add_(-1, topk_idxs, torch.ones_like(topk_idxs, dtype=torch.int8, device=topk_idxs.device))
        # Filter invalid bboxes
        count_tensor.masked_fill_(count_tensor > 1, 0)

        return count_tensor.to(metrics.dtype)

    def get_targets(self, gt_labels, gt_bboxes, target_gt_idx, fg_mask):
        """
        Compute target labels, target bounding boxes, and target scores for the positive anchor points.

        Args:
            gt_labels (Tensor): Ground truth labels of shape (b, max_num_obj, 1), where b is the
                                batch size and max_num_obj is the maximum number of objects.
            gt_bboxes (Tensor): Ground truth bounding boxes of shape (b, max_num_obj, 4).
            target_gt_idx (Tensor): Indices of the assigned ground truth objects for positive
                                    anchor points, with shape (b, h*w), where h*w is the total
                                    number of anchor points.
            fg_mask (Tensor): A boolean tensor of shape (b, h*w) indicating the positive
                              (foreground) anchor points.

        Returns:
            (Tuple[Tensor, Tensor, Tensor]): A tuple containing the following tensors:
                - target_labels (Tensor): Shape (b, h*w), containing the target labels for
                                          positive anchor points.
                - target_bboxes (Tensor): Shape (b, h*w, 4), containing the target bounding boxes
                                          for positive anchor points.
                - target_scores (Tensor): Shape (b, h*w, num_classes), containing the target scores
                                          for positive anchor points, where num_classes is the number
                                          of object classes.
        """

        # Assigned target labels, (b, 1)
        batch_ind = torch.arange(end=self.bs, dtype=torch.int64, device=gt_labels.device)[..., None]
        target_gt_idx = target_gt_idx + batch_ind * self.n_max_boxes  # (b, h*w)
        target_labels = gt_labels.long().flatten()[target_gt_idx]  # (b, h*w)

        # Assigned target boxes, (b, max_num_obj, 4) -> (b, h*w, 4)
        target_bboxes = gt_bboxes.view(-1, gt_bboxes.shape[-1])[target_gt_idx]

        # Assigned target scores
        target_labels.clamp_(0)

        # 10x faster than F.one_hot()
        target_scores = torch.zeros(
            (target_labels.shape[0], target_labels.shape[1], self.num_classes),
            dtype=torch.int64,
            device=target_labels.device,
        )  # (b, h*w, 80)
        target_scores.scatter_(2, target_labels.unsqueeze(-1), 1)

        fg_scores_mask = fg_mask[:, :, None].repeat(1, 1, self.num_classes)  # (b, h*w, 80)
        target_scores = torch.where(fg_scores_mask > 0, target_scores, 0)

        return target_labels, target_bboxes, target_scores

    @staticmethod
    def select_candidates_in_gts(xy_centers, gt_bboxes, eps=1e-9):
        """
        Select the positive anchor center in gt.

        Args:
            xy_centers (Tensor): shape(h*w, 2)
            gt_bboxes (Tensor): shape(b, n_boxes, 4)

        Returns:
            (Tensor): shape(b, n_boxes, h*w)
        """
        n_anchors = xy_centers.shape[0]
        bs, n_boxes, _ = gt_bboxes.shape
        lt, rb = gt_bboxes.view(-1, 1, 4).chunk(2, 2)  # left-top, right-bottom
        bbox_deltas = torch.cat((xy_centers[None] - lt, rb - xy_centers[None]), dim=2).view(bs, n_boxes, n_anchors, -1)
        # return (bbox_deltas.min(3)[0] > eps).to(gt_bboxes.dtype)
        return bbox_deltas.amin(3).gt_(eps)

    @staticmethod
    def select_highest_overlaps(mask_pos, overlaps, n_max_boxes):
        """
        If an anchor box is assigned to multiple gts, the one with the highest IoU will be selected.

        Args:
            mask_pos (Tensor): shape(b, n_max_boxes, h*w)
            overlaps (Tensor): shape(b, n_max_boxes, h*w)

        Returns:
            target_gt_idx (Tensor): shape(b, h*w)
            fg_mask (Tensor): shape(b, h*w)
            mask_pos (Tensor): shape(b, n_max_boxes, h*w)
        """
        # (b, n_max_boxes, h*w) -> (b, h*w)
        fg_mask = mask_pos.sum(-2)
        if fg_mask.max() > 1:  # one anchor is assigned to multiple gt_bboxes
            mask_multi_gts = (fg_mask.unsqueeze(1) > 1).expand(-1, n_max_boxes, -1)  # (b, n_max_boxes, h*w)
            max_overlaps_idx = overlaps.argmax(1)  # (b, h*w)

            is_max_overlaps = torch.zeros(mask_pos.shape, dtype=mask_pos.dtype, device=mask_pos.device)
            is_max_overlaps.scatter_(1, max_overlaps_idx.unsqueeze(1), 1)

            mask_pos = torch.where(mask_multi_gts, is_max_overlaps, mask_pos).float()  # (b, n_max_boxes, h*w)
            fg_mask = mask_pos.sum(-2)
        # Find each grid serve which gt(index)
        target_gt_idx = mask_pos.argmax(-2)  # (b, h*w)
        return target_gt_idx, fg_mask, mask_pos

__init__(topk=13, num_classes=80, alpha=1.0, beta=6.0, eps=1e-09)

تهيئة كائن TaskAlignedAssigner باستخدام معلمات فائقة قابلة للتخصيص.

شفرة المصدر في ultralytics/utils/tal.py
def __init__(self, topk=13, num_classes=80, alpha=1.0, beta=6.0, eps=1e-9):
    """Initialize a TaskAlignedAssigner object with customizable hyperparameters."""
    super().__init__()
    self.topk = topk
    self.num_classes = num_classes
    self.bg_idx = num_classes
    self.alpha = alpha
    self.beta = beta
    self.eps = eps

forward(pd_scores, pd_bboxes, anc_points, gt_labels, gt_bboxes, mask_gt)

حساب التعيين المحاذي للمهمة. الرمز المرجعي متاح في https://github.com/Nioolek/PPYOLOE_pytorch/blob/master/ppyoloe/assigner/tal_assigner.py.

البارامترات:

اسم نوع وصف افتراضي
pd_scores Tensor

الشكل (بكالوريوس ، num_total_anchors ، num_classes)

مطلوب
pd_bboxes Tensor

الشكل (بكالوريوس ، num_total_anchors ، 4)

مطلوب
anc_points Tensor

شكل (num_total_anchors ، 2)

مطلوب
gt_labels Tensor

الشكل (بكالوريوس ، n_max_boxes ، 1)

مطلوب
gt_bboxes Tensor

الشكل (بكالوريوس ، n_max_boxes ، 4)

مطلوب
mask_gt Tensor

الشكل (بكالوريوس ، n_max_boxes ، 1)

مطلوب

ارجاع:

اسم نوع وصف
target_labels Tensor

الشكل (بكالوريوس ، num_total_anchors)

target_bboxes Tensor

الشكل (بكالوريوس ، num_total_anchors ، 4)

target_scores Tensor

الشكل (بكالوريوس ، num_total_anchors ، num_classes)

fg_mask Tensor

الشكل (بكالوريوس ، num_total_anchors)

target_gt_idx Tensor

الشكل (بكالوريوس ، num_total_anchors)

شفرة المصدر في ultralytics/utils/tal.py
@torch.no_grad()
def forward(self, pd_scores, pd_bboxes, anc_points, gt_labels, gt_bboxes, mask_gt):
    """
    Compute the task-aligned assignment. Reference code is available at
    https://github.com/Nioolek/PPYOLOE_pytorch/blob/master/ppyoloe/assigner/tal_assigner.py.

    Args:
        pd_scores (Tensor): shape(bs, num_total_anchors, num_classes)
        pd_bboxes (Tensor): shape(bs, num_total_anchors, 4)
        anc_points (Tensor): shape(num_total_anchors, 2)
        gt_labels (Tensor): shape(bs, n_max_boxes, 1)
        gt_bboxes (Tensor): shape(bs, n_max_boxes, 4)
        mask_gt (Tensor): shape(bs, n_max_boxes, 1)

    Returns:
        target_labels (Tensor): shape(bs, num_total_anchors)
        target_bboxes (Tensor): shape(bs, num_total_anchors, 4)
        target_scores (Tensor): shape(bs, num_total_anchors, num_classes)
        fg_mask (Tensor): shape(bs, num_total_anchors)
        target_gt_idx (Tensor): shape(bs, num_total_anchors)
    """
    self.bs = pd_scores.shape[0]
    self.n_max_boxes = gt_bboxes.shape[1]

    if self.n_max_boxes == 0:
        device = gt_bboxes.device
        return (
            torch.full_like(pd_scores[..., 0], self.bg_idx).to(device),
            torch.zeros_like(pd_bboxes).to(device),
            torch.zeros_like(pd_scores).to(device),
            torch.zeros_like(pd_scores[..., 0]).to(device),
            torch.zeros_like(pd_scores[..., 0]).to(device),
        )

    mask_pos, align_metric, overlaps = self.get_pos_mask(
        pd_scores, pd_bboxes, gt_labels, gt_bboxes, anc_points, mask_gt
    )

    target_gt_idx, fg_mask, mask_pos = self.select_highest_overlaps(mask_pos, overlaps, self.n_max_boxes)

    # Assigned target
    target_labels, target_bboxes, target_scores = self.get_targets(gt_labels, gt_bboxes, target_gt_idx, fg_mask)

    # Normalize
    align_metric *= mask_pos
    pos_align_metrics = align_metric.amax(dim=-1, keepdim=True)  # b, max_num_obj
    pos_overlaps = (overlaps * mask_pos).amax(dim=-1, keepdim=True)  # b, max_num_obj
    norm_align_metric = (align_metric * pos_overlaps / (pos_align_metrics + self.eps)).amax(-2).unsqueeze(-1)
    target_scores = target_scores * norm_align_metric

    return target_labels, target_bboxes, target_scores, fg_mask.bool(), target_gt_idx

get_box_metrics(pd_scores, pd_bboxes, gt_labels, gt_bboxes, mask_gt)

حساب مقياس المحاذاة بالنظر إلى المربعات المحيطة بالحقيقة المتوقعة والأرضية.

شفرة المصدر في ultralytics/utils/tal.py
def get_box_metrics(self, pd_scores, pd_bboxes, gt_labels, gt_bboxes, mask_gt):
    """Compute alignment metric given predicted and ground truth bounding boxes."""
    na = pd_bboxes.shape[-2]
    mask_gt = mask_gt.bool()  # b, max_num_obj, h*w
    overlaps = torch.zeros([self.bs, self.n_max_boxes, na], dtype=pd_bboxes.dtype, device=pd_bboxes.device)
    bbox_scores = torch.zeros([self.bs, self.n_max_boxes, na], dtype=pd_scores.dtype, device=pd_scores.device)

    ind = torch.zeros([2, self.bs, self.n_max_boxes], dtype=torch.long)  # 2, b, max_num_obj
    ind[0] = torch.arange(end=self.bs).view(-1, 1).expand(-1, self.n_max_boxes)  # b, max_num_obj
    ind[1] = gt_labels.squeeze(-1)  # b, max_num_obj
    # Get the scores of each grid for each gt cls
    bbox_scores[mask_gt] = pd_scores[ind[0], :, ind[1]][mask_gt]  # b, max_num_obj, h*w

    # (b, max_num_obj, 1, 4), (b, 1, h*w, 4)
    pd_boxes = pd_bboxes.unsqueeze(1).expand(-1, self.n_max_boxes, -1, -1)[mask_gt]
    gt_boxes = gt_bboxes.unsqueeze(2).expand(-1, -1, na, -1)[mask_gt]
    overlaps[mask_gt] = self.iou_calculation(gt_boxes, pd_boxes)

    align_metric = bbox_scores.pow(self.alpha) * overlaps.pow(self.beta)
    return align_metric, overlaps

get_pos_mask(pd_scores, pd_bboxes, gt_labels, gt_bboxes, anc_points, mask_gt)

احصل على قناع in_gts ، (ب ، max_num_obj ، ح * ث).

شفرة المصدر في ultralytics/utils/tal.py
def get_pos_mask(self, pd_scores, pd_bboxes, gt_labels, gt_bboxes, anc_points, mask_gt):
    """Get in_gts mask, (b, max_num_obj, h*w)."""
    mask_in_gts = self.select_candidates_in_gts(anc_points, gt_bboxes)
    # Get anchor_align metric, (b, max_num_obj, h*w)
    align_metric, overlaps = self.get_box_metrics(pd_scores, pd_bboxes, gt_labels, gt_bboxes, mask_in_gts * mask_gt)
    # Get topk_metric mask, (b, max_num_obj, h*w)
    mask_topk = self.select_topk_candidates(align_metric, topk_mask=mask_gt.expand(-1, -1, self.topk).bool())
    # Merge all mask to a final mask, (b, max_num_obj, h*w)
    mask_pos = mask_topk * mask_in_gts * mask_gt

    return mask_pos, align_metric, overlaps

get_targets(gt_labels, gt_bboxes, target_gt_idx, fg_mask)

احسب التسميات المستهدفة والمربعات المحيطة المستهدفة ودرجات الهدف لنقاط الربط الموجبة.

البارامترات:

اسم نوع وصف افتراضي
gt_labels Tensor

تسميات الحقيقة الأرضية للشكل (ب ، max_num_obj ، 1) ، حيث b هي حجم الدفعة و max_num_obj هو الحد الأقصى لعدد الكائنات.

مطلوب
gt_bboxes Tensor

الحقيقة الأرضية المحيطة بمربعات الشكل (ب ، max_num_obj ، 4).

مطلوب
target_gt_idx Tensor

مؤشرات كائنات الحقيقة الأرضية المخصصة للإيجابية نقاط الربط ، مع الشكل (b ، hw) ، حيث hw هو الإجمالي عدد نقاط الربط.

مطلوب
fg_mask Tensor

منطقي tensor من الشكل (ب ، ح * ث) يشير إلى الموجب (المقدمة) نقاط الربط.

مطلوب

ارجاع:

نوع وصف
Tuple[Tensor, Tensor, Tensor]

مجموعة تحتوي على الموترات التالية: - target_labels (Tensor): الشكل (ب ، حw) ، التي تحتوي على التسميات المستهدفة ل نقاط الربط الإيجابية. - target_bboxes (Tensor): الشكل (b، hw، 4)، يحتوي على المربعات المحيطة بالهدف لنقاط الربط الإيجابية. - target_scores (Tensor): الشكل (ب ، ح * ث ، num_classes) ، يحتوي على الدرجات المستهدفة بالنسبة لنقاط الربط الموجبة، حيث num_classes هو الرقم من فئات الكائنات.

شفرة المصدر في ultralytics/utils/tal.py
def get_targets(self, gt_labels, gt_bboxes, target_gt_idx, fg_mask):
    """
    Compute target labels, target bounding boxes, and target scores for the positive anchor points.

    Args:
        gt_labels (Tensor): Ground truth labels of shape (b, max_num_obj, 1), where b is the
                            batch size and max_num_obj is the maximum number of objects.
        gt_bboxes (Tensor): Ground truth bounding boxes of shape (b, max_num_obj, 4).
        target_gt_idx (Tensor): Indices of the assigned ground truth objects for positive
                                anchor points, with shape (b, h*w), where h*w is the total
                                number of anchor points.
        fg_mask (Tensor): A boolean tensor of shape (b, h*w) indicating the positive
                          (foreground) anchor points.

    Returns:
        (Tuple[Tensor, Tensor, Tensor]): A tuple containing the following tensors:
            - target_labels (Tensor): Shape (b, h*w), containing the target labels for
                                      positive anchor points.
            - target_bboxes (Tensor): Shape (b, h*w, 4), containing the target bounding boxes
                                      for positive anchor points.
            - target_scores (Tensor): Shape (b, h*w, num_classes), containing the target scores
                                      for positive anchor points, where num_classes is the number
                                      of object classes.
    """

    # Assigned target labels, (b, 1)
    batch_ind = torch.arange(end=self.bs, dtype=torch.int64, device=gt_labels.device)[..., None]
    target_gt_idx = target_gt_idx + batch_ind * self.n_max_boxes  # (b, h*w)
    target_labels = gt_labels.long().flatten()[target_gt_idx]  # (b, h*w)

    # Assigned target boxes, (b, max_num_obj, 4) -> (b, h*w, 4)
    target_bboxes = gt_bboxes.view(-1, gt_bboxes.shape[-1])[target_gt_idx]

    # Assigned target scores
    target_labels.clamp_(0)

    # 10x faster than F.one_hot()
    target_scores = torch.zeros(
        (target_labels.shape[0], target_labels.shape[1], self.num_classes),
        dtype=torch.int64,
        device=target_labels.device,
    )  # (b, h*w, 80)
    target_scores.scatter_(2, target_labels.unsqueeze(-1), 1)

    fg_scores_mask = fg_mask[:, :, None].repeat(1, 1, self.num_classes)  # (b, h*w, 80)
    target_scores = torch.where(fg_scores_mask > 0, target_scores, 0)

    return target_labels, target_bboxes, target_scores

iou_calculation(gt_bboxes, pd_bboxes)

حساب IoU للمربعات المحيطة الأفقية.

شفرة المصدر في ultralytics/utils/tal.py
def iou_calculation(self, gt_bboxes, pd_bboxes):
    """IoU calculation for horizontal bounding boxes."""
    return bbox_iou(gt_bboxes, pd_bboxes, xywh=False, CIoU=True).squeeze(-1).clamp_(0)

select_candidates_in_gts(xy_centers, gt_bboxes, eps=1e-09) staticmethod

حدد مركز المرساة الموجب في gt.

البارامترات:

اسم نوع وصف افتراضي
xy_centers Tensor

الشكل (ح * ث ، 2)

مطلوب
gt_bboxes Tensor

الشكل (ب ، n_boxes ، 4)

مطلوب

ارجاع:

نوع وصف
Tensor

الشكل (ب ، n_boxes ، ح * ث)

شفرة المصدر في ultralytics/utils/tal.py
@staticmethod
def select_candidates_in_gts(xy_centers, gt_bboxes, eps=1e-9):
    """
    Select the positive anchor center in gt.

    Args:
        xy_centers (Tensor): shape(h*w, 2)
        gt_bboxes (Tensor): shape(b, n_boxes, 4)

    Returns:
        (Tensor): shape(b, n_boxes, h*w)
    """
    n_anchors = xy_centers.shape[0]
    bs, n_boxes, _ = gt_bboxes.shape
    lt, rb = gt_bboxes.view(-1, 1, 4).chunk(2, 2)  # left-top, right-bottom
    bbox_deltas = torch.cat((xy_centers[None] - lt, rb - xy_centers[None]), dim=2).view(bs, n_boxes, n_anchors, -1)
    # return (bbox_deltas.min(3)[0] > eps).to(gt_bboxes.dtype)
    return bbox_deltas.amin(3).gt_(eps)

select_highest_overlaps(mask_pos, overlaps, n_max_boxes) staticmethod

إذا تم تعيين مربع ربط إلى GTS متعددة ، تحديد المربع الذي يحتوي على أعلى IoU.

البارامترات:

اسم نوع وصف افتراضي
mask_pos Tensor

الشكل (ب ، n_max_boxes ، ح * ث)

مطلوب
overlaps Tensor

الشكل (ب ، n_max_boxes ، ح * ث)

مطلوب

ارجاع:

اسم نوع وصف
target_gt_idx Tensor

الشكل (ب ، ح * ث)

fg_mask Tensor

الشكل (ب ، ح * ث)

mask_pos Tensor

الشكل (ب ، n_max_boxes ، ح * ث)

شفرة المصدر في ultralytics/utils/tal.py
@staticmethod
def select_highest_overlaps(mask_pos, overlaps, n_max_boxes):
    """
    If an anchor box is assigned to multiple gts, the one with the highest IoU will be selected.

    Args:
        mask_pos (Tensor): shape(b, n_max_boxes, h*w)
        overlaps (Tensor): shape(b, n_max_boxes, h*w)

    Returns:
        target_gt_idx (Tensor): shape(b, h*w)
        fg_mask (Tensor): shape(b, h*w)
        mask_pos (Tensor): shape(b, n_max_boxes, h*w)
    """
    # (b, n_max_boxes, h*w) -> (b, h*w)
    fg_mask = mask_pos.sum(-2)
    if fg_mask.max() > 1:  # one anchor is assigned to multiple gt_bboxes
        mask_multi_gts = (fg_mask.unsqueeze(1) > 1).expand(-1, n_max_boxes, -1)  # (b, n_max_boxes, h*w)
        max_overlaps_idx = overlaps.argmax(1)  # (b, h*w)

        is_max_overlaps = torch.zeros(mask_pos.shape, dtype=mask_pos.dtype, device=mask_pos.device)
        is_max_overlaps.scatter_(1, max_overlaps_idx.unsqueeze(1), 1)

        mask_pos = torch.where(mask_multi_gts, is_max_overlaps, mask_pos).float()  # (b, n_max_boxes, h*w)
        fg_mask = mask_pos.sum(-2)
    # Find each grid serve which gt(index)
    target_gt_idx = mask_pos.argmax(-2)  # (b, h*w)
    return target_gt_idx, fg_mask, mask_pos

select_topk_candidates(metrics, largest=True, topk_mask=None)

حدد أفضل المرشحين ل K بناء على المقاييس المحددة.

البارامترات:

اسم نوع وصف افتراضي
metrics Tensor

A tensor من الشكل (ب ، max_num_obj ، حث) ، حيث b هو حجم الدفعة ، max_num_obj هو الحد الأقصى لعدد الكائنات ، و hw يمثل إجمالي عدد نقاط الربط.

مطلوب
largest bool

إذا كان صحيحا ، فحدد أكبر القيم ؛ وإلا، فحدد أصغر القيم.

True
topk_mask Tensor

منطقية اختيارية tensor من الشكل (ب ، max_num_obj ، توبك) ، حيث Topk هو عدد أفضل المرشحين للنظر فيها. إذا لم يتم توفيره ، يتم حساب قيم TOP-K تلقائيا بناء على المقاييس المحددة.

None

ارجاع:

نوع وصف
Tensor

A tensor من الشكل (ب ، max_num_obj ، H * W) يحتوي على المرشحين المختارين من TOP-K.

شفرة المصدر في ultralytics/utils/tal.py
def select_topk_candidates(self, metrics, largest=True, topk_mask=None):
    """
    Select the top-k candidates based on the given metrics.

    Args:
        metrics (Tensor): A tensor of shape (b, max_num_obj, h*w), where b is the batch size,
                          max_num_obj is the maximum number of objects, and h*w represents the
                          total number of anchor points.
        largest (bool): If True, select the largest values; otherwise, select the smallest values.
        topk_mask (Tensor): An optional boolean tensor of shape (b, max_num_obj, topk), where
                            topk is the number of top candidates to consider. If not provided,
                            the top-k values are automatically computed based on the given metrics.

    Returns:
        (Tensor): A tensor of shape (b, max_num_obj, h*w) containing the selected top-k candidates.
    """

    # (b, max_num_obj, topk)
    topk_metrics, topk_idxs = torch.topk(metrics, self.topk, dim=-1, largest=largest)
    if topk_mask is None:
        topk_mask = (topk_metrics.max(-1, keepdim=True)[0] > self.eps).expand_as(topk_idxs)
    # (b, max_num_obj, topk)
    topk_idxs.masked_fill_(~topk_mask, 0)

    # (b, max_num_obj, topk, h*w) -> (b, max_num_obj, h*w)
    count_tensor = torch.zeros(metrics.shape, dtype=torch.int8, device=topk_idxs.device)
    ones = torch.ones_like(topk_idxs[:, :, :1], dtype=torch.int8, device=topk_idxs.device)
    for k in range(self.topk):
        # Expand topk_idxs for each value of k and add 1 at the specified positions
        count_tensor.scatter_add_(-1, topk_idxs[:, :, k : k + 1], ones)
    # count_tensor.scatter_add_(-1, topk_idxs, torch.ones_like(topk_idxs, dtype=torch.int8, device=topk_idxs.device))
    # Filter invalid bboxes
    count_tensor.masked_fill_(count_tensor > 1, 0)

    return count_tensor.to(metrics.dtype)



ultralytics.utils.tal.RotatedTaskAlignedAssigner

قواعد: TaskAlignedAssigner

شفرة المصدر في ultralytics/utils/tal.py
class RotatedTaskAlignedAssigner(TaskAlignedAssigner):
    def iou_calculation(self, gt_bboxes, pd_bboxes):
        """IoU calculation for rotated bounding boxes."""
        return probiou(gt_bboxes, pd_bboxes).squeeze(-1).clamp_(0)

    @staticmethod
    def select_candidates_in_gts(xy_centers, gt_bboxes):
        """
        Select the positive anchor center in gt for rotated bounding boxes.

        Args:
            xy_centers (Tensor): shape(h*w, 2)
            gt_bboxes (Tensor): shape(b, n_boxes, 5)

        Returns:
            (Tensor): shape(b, n_boxes, h*w)
        """
        # (b, n_boxes, 5) --> (b, n_boxes, 4, 2)
        corners = xywhr2xyxyxyxy(gt_bboxes)
        # (b, n_boxes, 1, 2)
        a, b, _, d = corners.split(1, dim=-2)
        ab = b - a
        ad = d - a

        # (b, n_boxes, h*w, 2)
        ap = xy_centers - a
        norm_ab = (ab * ab).sum(dim=-1)
        norm_ad = (ad * ad).sum(dim=-1)
        ap_dot_ab = (ap * ab).sum(dim=-1)
        ap_dot_ad = (ap * ad).sum(dim=-1)
        return (ap_dot_ab >= 0) & (ap_dot_ab <= norm_ab) & (ap_dot_ad >= 0) & (ap_dot_ad <= norm_ad)  # is_in_box

iou_calculation(gt_bboxes, pd_bboxes)

حساب IoU للمربعات المحيطة التي تم تدويرها.

شفرة المصدر في ultralytics/utils/tal.py
def iou_calculation(self, gt_bboxes, pd_bboxes):
    """IoU calculation for rotated bounding boxes."""
    return probiou(gt_bboxes, pd_bboxes).squeeze(-1).clamp_(0)

select_candidates_in_gts(xy_centers, gt_bboxes) staticmethod

حدد مركز الربط الموجب في gt للمربعات المحيطة التي تم تدويرها.

البارامترات:

اسم نوع وصف افتراضي
xy_centers Tensor

الشكل (ح * ث ، 2)

مطلوب
gt_bboxes Tensor

الشكل (ب ، n_boxes ، 5)

مطلوب

ارجاع:

نوع وصف
Tensor

الشكل (ب ، n_boxes ، ح * ث)

شفرة المصدر في ultralytics/utils/tal.py
@staticmethod
def select_candidates_in_gts(xy_centers, gt_bboxes):
    """
    Select the positive anchor center in gt for rotated bounding boxes.

    Args:
        xy_centers (Tensor): shape(h*w, 2)
        gt_bboxes (Tensor): shape(b, n_boxes, 5)

    Returns:
        (Tensor): shape(b, n_boxes, h*w)
    """
    # (b, n_boxes, 5) --> (b, n_boxes, 4, 2)
    corners = xywhr2xyxyxyxy(gt_bboxes)
    # (b, n_boxes, 1, 2)
    a, b, _, d = corners.split(1, dim=-2)
    ab = b - a
    ad = d - a

    # (b, n_boxes, h*w, 2)
    ap = xy_centers - a
    norm_ab = (ab * ab).sum(dim=-1)
    norm_ad = (ad * ad).sum(dim=-1)
    ap_dot_ab = (ap * ab).sum(dim=-1)
    ap_dot_ad = (ap * ad).sum(dim=-1)
    return (ap_dot_ab >= 0) & (ap_dot_ab <= norm_ab) & (ap_dot_ad >= 0) & (ap_dot_ad <= norm_ad)  # is_in_box



ultralytics.utils.tal.make_anchors(feats, strides, grid_cell_offset=0.5)

إنشاء نقاط ارتساء من الميزات.

شفرة المصدر في ultralytics/utils/tal.py
def make_anchors(feats, strides, grid_cell_offset=0.5):
    """Generate anchors from features."""
    anchor_points, stride_tensor = [], []
    assert feats is not None
    dtype, device = feats[0].dtype, feats[0].device
    for i, stride in enumerate(strides):
        _, _, h, w = feats[i].shape
        sx = torch.arange(end=w, device=device, dtype=dtype) + grid_cell_offset  # shift x
        sy = torch.arange(end=h, device=device, dtype=dtype) + grid_cell_offset  # shift y
        sy, sx = torch.meshgrid(sy, sx, indexing="ij") if TORCH_1_10 else torch.meshgrid(sy, sx)
        anchor_points.append(torch.stack((sx, sy), -1).view(-1, 2))
        stride_tensor.append(torch.full((h * w, 1), stride, dtype=dtype, device=device))
    return torch.cat(anchor_points), torch.cat(stride_tensor)



ultralytics.utils.tal.dist2bbox(distance, anchor_points, xywh=True, dim=-1)

تحويل المسافة (ltrb) إلى مربع (xywh أو xyxy).

شفرة المصدر في ultralytics/utils/tal.py
def dist2bbox(distance, anchor_points, xywh=True, dim=-1):
    """Transform distance(ltrb) to box(xywh or xyxy)."""
    lt, rb = distance.chunk(2, dim)
    x1y1 = anchor_points - lt
    x2y2 = anchor_points + rb
    if xywh:
        c_xy = (x1y1 + x2y2) / 2
        wh = x2y2 - x1y1
        return torch.cat((c_xy, wh), dim)  # xywh bbox
    return torch.cat((x1y1, x2y2), dim)  # xyxy bbox



ultralytics.utils.tal.bbox2dist(anchor_points, bbox, reg_max)

تحويل bbox (xyxy) إلى dist (ltrb).

شفرة المصدر في ultralytics/utils/tal.py
def bbox2dist(anchor_points, bbox, reg_max):
    """Transform bbox(xyxy) to dist(ltrb)."""
    x1y1, x2y2 = bbox.chunk(2, -1)
    return torch.cat((anchor_points - x1y1, x2y2 - anchor_points), -1).clamp_(0, reg_max - 0.01)  # dist (lt, rb)



ultralytics.utils.tal.dist2rbox(pred_dist, pred_angle, anchor_points, dim=-1)

فك تشفير إحداثيات المربع المحيط بالكائن المتوقع من نقاط الربط والتوزيع.

البارامترات:

اسم نوع وصف افتراضي
pred_dist Tensor

المسافة الدوارة المتوقعة ، (bs ، h * w ، 4).

مطلوب
pred_angle Tensor

الزاوية المتوقعة ، (bs ، h * w ، 1).

مطلوب
anchor_points Tensor

نقاط الربط ، (h * w ، 2).

مطلوب

ارجاع: (torch.Tensor): المربعات المحيطة الدوارة المتوقعة ، (bs ، h * w ، 4).

شفرة المصدر في ultralytics/utils/tal.py
def dist2rbox(pred_dist, pred_angle, anchor_points, dim=-1):
    """
    Decode predicted object bounding box coordinates from anchor points and distribution.

    Args:
        pred_dist (torch.Tensor): Predicted rotated distance, (bs, h*w, 4).
        pred_angle (torch.Tensor): Predicted angle, (bs, h*w, 1).
        anchor_points (torch.Tensor): Anchor points, (h*w, 2).
    Returns:
        (torch.Tensor): Predicted rotated bounding boxes, (bs, h*w, 4).
    """
    lt, rb = pred_dist.split(2, dim=dim)
    cos, sin = torch.cos(pred_angle), torch.sin(pred_angle)
    # (bs, h*w, 1)
    xf, yf = ((rb - lt) / 2).split(1, dim=dim)
    x, y = xf * cos - yf * sin, xf * sin + yf * cos
    xy = torch.cat([x, y], dim=dim) + anchor_points
    return torch.cat([xy, lt + rb], dim=dim)





Created 2023-11-12, Updated 2024-06-02
Authors: glenn-jocher (6), Burhan-Q (1), Laughing-q (1)